Electromagnetic tomography solutions for scanning head

ABSTRACT

An electromagnetic tomography system for gathering measurement data pertaining to a human head includes an image chamber unit, a control system, and a housing. The image chamber unit includes an antenna assembly defining a horizontally-oriented imaging chamber and including an array of antennas arranged around the imaging chamber. The antennas include at least some transmitting antennas and some receiving antennas. The control system causes the transmitting antennas to transmit a low power electromagnetic field that is received by the receiving antennas after passing through a patient&#39;s head in the imaging chamber. A data tensor is produced that may be inversed to reconstruct a 3D distribution of dielectric properties within the head and to create an image. The housing at least partially contains the antenna assembly and has a front entry opening into the imaging chamber. The head is inserted horizontally through the front entry opening and into the imaging chamber.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of, and claims priority under to,U.S. patent application Ser. No. 14/086,968 to Semenov, filed Nov. 21,2013, which was published Jun. 5, 2014 as U.S. Patent ApplicationPublication No. 2014/0155740 A1, now U.S. Pat. No. 9,414,749, and which'968 application is a nonprovisional patent application of, and claimspriority under 35 U.S.C. §119(e) to, U.S. provisional patent applicationSer. No. 61/729,319 to Semenov, filed Nov. 21, 2012 and entitled“ELECTROMAGNETIC TOMOGRAPHY SOLUTIONS FOR SCANNING HEAD.” The foregoingpublication and applications are each incorporated herein by referencein their entirety. Additionally, each of the following patents, patentapplications and patent application publications is incorporated byreference herein in its entirety:

-   -   (a) U.S. Pat. No. 7,239,731 to Semenov et al., issued Jul. 3,        2007 and entitled “SYSTEM AND METHOD FOR NON-DESTRUCTIVE        FUNCTIONAL IMAGING AND MAPPING OF ELECTRICAL EXCITATION OF        BIOLOGICAL TISSUES USING ELECTROMAGNETIC FIELD TOMOGRAPHY AND        SPECTROSCOPY,” which is intended, at least, to provide        background and technical information with regard to the systems        and environments of the inventions of the current patent        application;    -   (b) U.S. Patent Application Publication No. 2012/0010493 A1,        which was published Jan. 12, 2012 based on U.S. patent        application Ser. No. 13/173,078 to Semenov, filed Jun. 30, 2011        and entitled “SYSTEMS AND METHODS OF 4D ELECTROMAGNETIC        TOMOGRAPHIC (EMT) DIFFERENTIAL (DYNAMIC) FUSED IMAGING,” which        is intended, at least, to provide explanation of the use of “4D”        technology in EMT systems, including with regard to inventions        of the current patent application; and    -   (c) U.S. Pat. No. 9,072,449 to Semenov et al., issued Jul. 7,        2015 and entitled “WEARABLE/MAN-PORTABLE ELECTROMAGNETIC        TOMOGRAPHIC IMAGING,” which was based on U.S. patent application        Ser. No. 13/894,395 to Semenov, filed May 14, 2013 and        previously published on Sep. 18, 2014 as U.S. Patent Application        Publication 2014/0276012, which is intended, at least, to        explain wearable and/or man-portable components of an        electromagnetic tomographic imaging system.

COPYRIGHT STATEMENT

All of the material in this patent document is subject to copyrightprotection under the copyright laws of the United States and othercountries. The copyright owner has no objection to the facsimilereproduction by anyone of the patent document or the patent disclosure,as it appears in official governmental records but, otherwise, all othercopyright rights whatsoever are reserved.

BACKGROUND OF THE PRESENT INVENTION

Field of the Present Invention

The present invention relates generally to electromagnetic tomography,and, in particular but not exclusively, to electromagnetic tomographysolutions for use with the heads of humans and other animals.

Background

Stroke is the 2_(nd) leading cause of death after ischemic heartdiseases, and is responsible for 4.4 million deaths (9 percent of alldeaths) each year. According to American Heart Association/StrokeAssociation, every 40 seconds someone in America has a stroke. Every 3minutes, someone dies of one. Stroke kills more than 137,000 Americans ayear. About 795,000 Americans each year suffer a new or recurrentstroke. In Europe there are approximately 1.1 million deaths each year;in the EU there are approximately 460,000 deaths each year caused bystroke disease.

Stroke is a leading cause of serious, long-term disabilities worldwide,causing significant economic impact. The Potential Years of Life Lost(PYLL) calculated by OECD shows a significant number, which should bepreventable.

Acute ischemic strokes account for about 85% of all strokes; each beginswith a blood clot (thrombus) forming in the circulatory system at a sitedistant from the brain. The clot breaks away from this distant siteforming an embolus which then travels through the circulatory system; onreaching the brain, the embolus lodges in the small vessels,interrupting blood flow to a portion of brain tissue. With thisreduction in blood flow, tissue damage quickly ensues. Clinicalmanagement of stroke has been enhanced by the use of thrombolytics (clotbusters) combined with the application of brain imaging techniques thatreveal the pathophysiological changes in brain tissue that result fromthe stroke. In particular, the clinical decision to use a thrombolyticmust be made within 3 hours of the onset of symptoms and requires a firmdiagnosis of an ischemic stroke. This clinical decision currently relieson imaging methods such as computed tomography (CT) and magneticresonance imaging (MRI) to reliably determine ischemic perfusionchanges. Subsequent management of the stroke is enhanced by imaging theextent of the area of brain tissue with compromised blood flow. Currentclinical imaging methods, including CT, positron emission tomography(PET) and MM each offer useful information on tissue properties relatedto perfusion, ischemia and infarction.

While each of these methods has its own advantages, none currentlyoffers a rapid or cost effective imaging solution that can be madewidely available at the “bedside” in the emergency department or tofirst response paramedical services. Electromagnetic tomography (EMT),on the other hand, is a relatively recent imaging modality with greatpotential for biomedical applications, including a non-invasiveassessment of functional and pathological conditions of biologicaltissues. Using EMT, biological tissues are differentiated and,consequentially, can be imaged based on the differences in tissuedielectric properties. The dependence of tissue dielectric propertiesfrom its various functional and pathological conditions, such as bloodand oxygen contents, ischemia and infarction malignancies has beendemonstrated.

Two-dimensional (2D), three-dimensional (3D) and even “four-dimensional”(4D) EMT systems and methods of image reconstruction have been developedover the last decade or more. Feasibility of the technology for variousbiomedical applications has been demonstrated, for example, for cardiacimaging and extremities imaging.

As in any biomedical imaging, the classical EMT imaging scenarioconsists of cycles of measurements of complex signals, as scattered by abiologic object under study, obtained from a plurality of transmitterslocated at various points around the object and measured on a pluralityof receivers located at various points around the object. This isillustrated in FIG. 1. As recounted elsewhere herein, the measuredmatrix of scattered EM signals may then be used in image reconstructionmethods in order to reconstruct 3D distribution of dielectric propertiesof the object, i.e., to construct a 3D image of the object.

Generally, it is very important for image reconstruction to preciselydescribe a distribution of EM field with an imaging domain 21. Thedistribution of EM field with an imaging chamber is a very complexphenomenon, even when there is no object of interest inside.

FIG. 2 is a schematic view of a prior art EM field tomographicspectroscopic system 10, and FIG. 3 is a schematic diagram illustratingthe operation of the system of FIG. 2 in a two-dimensional context. Sucha system 10 could carry out functional imaging of biological tissues andcould also be used for a non-invasive mapping of electrical excitationof biological tissues 19 using a sensitive (contrast) material (solutionor nanoparticles) injected into the biological tissue 19 or carried inthe circulation system, characterized by having dielectric propertiesthat are a function of electrical field, generated by biological excitedtissue 19. As illustrated in FIG. 2, the system 10 included a working orimaging chamber 12, a plurality of “EM field source-detector” clusters26, an equal number of intermediate frequency (“IF”) detector clusters28, and a control system (not shown). Although only two EM fieldsource-detector clusters 26 and two IF detector clusters 28 are shown, amuch larger number of each are actually used.

The imaging chamber 12 is a watertight vessel of sufficient size toaccommodate a human body or one or more parts of a human body togetherwith a matching liquid. The imaging chamber 12 and its EM field clusters26, as well as the IF detector clusters 28, have sometimes been mountedon carts in order to permit the respective components to be moved ifnecessary, and the carts may then be locked in place to providestability.

Oversimplified, the system 10 operates as follows. An object of interest(e.g., biological tissue) is placed in the imaging domain 21. Thetransmitting hardware generates electromagnetic (EM) radiation anddirects it to one of the antennas. This antenna transmitselectromagnetic waves into imaging domain 21, and all of the otherantennas receive electromagnetic waves that have passed through someportion of the imaging domain 21. The receiving hardware detects theresulting signal(s), and then the same cycle is repeated for the nextantenna and the next one until all antennas have served as atransmitter. The end result is a matrix of complex data which istransmitted to one or more computers in the control system that processthe data to produce an image of the object 19 in the imaging domain 21.An algorithm called an “inversion” algorithm is utilized in thisprocess.

Electromagnetic tomography uses non-ionizing electromagnetic radiationto differentiate between human tissues. Using a compact antenna design,it creates a low power EM field (less than used in cellular phones),which interacts with the biological object and is then measured bysensors. Special imaging algorithms are then used to inverse a “datatensor” and reconstruct a 3D distribution of dielectric propertieswithin a biological subject inside the EM field—i.e. to obtain aso-called “image tensor” or, simply, an image of the object. Theseimaging algorithms are in very general terms similar to the ones used inclassical imaging methods (such as back-projection method used inComputed Tomography (CT)). However, the wave nature of propagation of EMwaves needs to be accounted for in imaging algorithms, siginificantlycomplicating them. In addition, EMT imaging of the brain presents asignificant challenge, as the brain is an object of interest that islocated inside a high dielectric contrast shield, comprising the skull(with low dielectric contrast (∈˜10-15) and cerebral spinal fluid (withhigh ∈˜55-60)).

The images are possible due to the contrast in dielectric properties ofvarious tissues. The contrasts in dielectric properties can also bemapped between normal tissues and tissues under different functional orpathological conditions (functional contrasts). Examples include:malignancies in breast, liver and lung; tissue blood content/flow;hypoxia; ischemia; infarction; compartmental injury; stroke; and braintrauma.

Unfortunately, existing EMT solutions are not well-suited for certainapplications. In this regard, FIGS. 4 and 5 are schematic illustrationsof two three-dimensional settings for the system of FIG. 2. As evidenttherefrom, conventional EMT imaging chambers are oriented vertically soas to hold the matching liquid. Such an arrangement makes it verydifficult to use the technology to image a human head because of theinconvenience of positioning a patient's head in the imaging chamber.This is particularly problematic in the emergency setting, where apatient may not be capable of positioning himself in an arrangement thatallows him to insert his head into the imaging chamber. As a result,current implementations of EMT technology are not very suitable for usein diagnosing or treating stroke. Thus, a need exists for a safe,portable and cost-effective supplement to current imaging modalities foracute and chronic assessment of cerebral vascular diseases, includingstroke. In particular, a need exists for the use of EMTensor technologyin a mobile setting, such as in an ambulance or helicopter, andcontinual, safe and cost effective monitoring of an efficacy oftreatment in ICUs and other medical facilities.

SUMMARY OF THE PRESENT INVENTION

Broadly defined, the present invention according to one aspect is anelectromagnetic tomography (EMT) system for imaging a human head, asshown and described.

Broadly defined, the present invention according to another aspect is anelectromagnetic tomography (EMT) system for imaging a human head,including: an integrated scanning apparatus; and a hub computer system.

In a feature of this aspect, the integrated scanning apparatus includesan imaging chamber. In a further feature, the imaging chamber isvertically oriented such that a human head may be inserted horizontallyinto the imaging chamber.

In another feature of this aspect, the integrated scanning apparatushouses a plurality of rings of antennas. In further features, each ringof the plurality of rings is vertically oriented; the rings of theplurality of rings are concentric with each other; and/or the ringsinclude a first set of rings of antennas that are transmitting andreceiving antennas, and a second set of rings of antennas that arereceiving antennas only.

In further features pertaining to the first and second sets of rings,the second set of rings is divided into two subsets, and the first setof rings of antennas is located between the two subsets; the firstsubset of rings includes one ring; and/or the second subset of ringsincludes four rings.

In a further feature pertaining to the rings, each ring includes 32antennas.

In another feature of this aspect, the integrated scanning apparatus isman-portable.

In another feature of this aspect, the integrated scanning apparatus andhub computer system are transportable. In a further feature, theintegrated scanning apparatus and hub computer system are mobile.

Broadly defined, the present invention according to another aspect is anintegrated scanning apparatus for imaging a human head in anelectromagnetic tomography (EMT) system, as shown and described.

Broadly defined, the present invention according to another aspect is anintegrated scanning apparatus for imaging a human head in anelectromagnetic tomography (EMT) system, including: a housing defining avertically oriented imaging chamber in which a human head may beinserted horizontally; and an array of antennas.

In a feature of this aspect, the integrated scanning apparatus istransportable. In a further feature, the integrated scanning apparatusis mobile. In a still further feature, the integrated scanning apparatusis man-portable.

In another feature of this aspect, the array of antennas is arranged ina plurality of rings of antennas. In further features, the rings of theplurality of rings are concentric with each other; the rings include afirst set of rings of antennas that are transmitting and receivingantennas, and a second set of rings of antennas that are receivingantennas only; and/or each ring includes 32 antennas.

In further features pertaining to the first and second sets of rings,the second set of rings is divided into two subsets, and the first setof rings of antennas is located between the two subsets; the firstsubset of rings includes one ring; and/or the second subset of ringsincludes four rings.

Broadly defined, the present invention according to another aspect is awearable scanning apparatus for imaging a human head in anelectromagnetic tomography (EMT) system, as shown and described.

Broadly defined, the present invention according to another aspect is amethod of treating a stroke patient using an electromagnetic tomography(EMT) system, as shown and described.

Broadly defined, the present invention according to another aspect is amethod of treating a stroke patient using an electromagnetic tomography(EMT) system, including: in response to an emergency report and requestfrom or on behalf of stroke patient, providing an ambulance equippedwith a scanning apparatus for imaging a human head in an electromagnetictomography (EMT) system; placing the scanning apparatus on or around thestroke patient's head; carrying out an EMT scanning process; providingdata from the EMT scanning process to a hub computer system; producingEMT image results based on the provided data; and providing the EMTimage results to a medical practitioner at a treatment center for use indiagnosing or treating the stroke patient upon the patient's arrival atthe treatment center.

Broadly defined, the present invention according to another aspect is animage chamber unit for gathering measurement data pertaining to a humanhead in an electromagnetic tomography (EMT) system, including: anantenna assembly at least partially defining a horizontally-orientedimaging chamber and including an array of antennas arranged around theimaging chamber, the array of antennas including at least sometransmitting antennas and at least some receiving antennas, wherein thetransmitting antennas transmit a low power electromagnetic field,wherein the receiving antennas receive the low power electromagneticfield after passing through a human head in the imaging chamber andprovide corresponding signals to a control system so as to produce adata tensor that may be inversed to reconstruct a 3D distribution ofdielectric properties within the human head and thereby to create animage of the object; and a housing, at least partially containing theantenna assembly, having a front entry opening into the imaging chamber.The head of a human patient may be inserted horizontally through thefront entry opening and into the imaging chamber.

In a feature of this aspect the antenna assembly includes a plurality ofantenna disks, each antenna disk including an array of antennas. Eachantenna disk includes a center opening, wherein the imaging chamber isat least partially defined by the plurality of center openings. Theantenna disk center openings are circular and collectively define acylindrical portion of the imaging chamber. The antenna assembly furtherincludes a back disk attached to a rear of the antenna disks, whereinthe back disk closes and defines a rear of the horizontally-orientedimaging chamber.

In a further feature, the array of antennas on each antenna disk isarranged in a ring whose center axis is oriented horizontally. The ringsinclude a first set of rings of antennas that are transmitting andreceiving antennas, and a second set of rings of antennas that arereceiving antennas only. The second set of rings is divided into twosubsets, and wherein the first set of rings of antennas is locatedbetween the two subsets. The first subset of rings includes one ring.The second subset of rings includes four rings. Each ring includes 32antennas.

In another feature of this aspect, the image chamber unit furtherincludes a flexible membrane separating a front portion of the imagingchamber from a rear portion of the imaging chamber. The flexiblemembrane conforms to a portion of the shape of a human head when thehuman head is inserted through the front entry opening and into thefront portion of the imaging chamber. The rear portion of the imagingchamber is filled with a liquid. The liquid is a matching liquid for anelectromagnetic tomography operation. The matching liquid is a mixtureof glycerol, water and brine. The antenna assembly further includes aback disk attached to a rear of a plurality of antenna disks, andwherein the back disk includes at least one inlet for pumping thematching liquid into the rear portion of the imaging chamber. In afurther feature of this aspect the image chamber unit of, furtherincludes a catch basin disposed adjacent the entry opening so as toreceive liquid leaking from the front of the imaging chamber. The catchbasin includes a drain tube. In a further feature of this aspect theimage chamber further includes a sanitary protective cap disposed infront of and against the flexible membrane to provide sanitaryprotection for a human head when the human head is inserted into thefront entry opening and against the membrane. In yet a further featureof this aspect the image chamber further includes a protective ringaround the entry opening to protect the human head from injury wheninserting the head through the entry opening.

Broadly defined, the present invention according to another aspect is anelectromagnetic tomography (EMT) system for gathering measurement datapertaining to a human head, including: an image chamber unit includingan antenna assembly at least partially defining a horizontally-orientedimaging chamber and including an array of antennas arranged around theimaging chamber, the array of antennas including at least sometransmitting antennas and at least some receiving antennas, a controlsystem that causes the transmitting antennas to transmit a low powerelectromagnetic field that is received by the receiving antennas afterpassing through a human head in the imaging chamber and produces a datatensor from resulting signals that may be inversed to reconstruct a 3Ddistribution of dielectric properties within the human head and therebyto create an image of the object; and a housing, at least partiallycontaining the antenna assembly, having a front entry opening into theimaging chamber. The head of a human patient may be insertedhorizontally through the front entry opening and into the imagingchamber.

In a feature of this aspect the antenna assembly includes a plurality ofantenna disks, each antenna disk including an array of antennas. Eachantenna disk includes a center opening, wherein the imaging chamber isat least partially defined by the plurality of center openings. Theantenna disk center openings are circular and collectively define acylindrical portion of the imaging chamber. The antenna assembly furtherincludes a back disk attached to a rear of the antenna disks, whereinthe back disk closes and defines a rear of the horizontally-orientedimaging chamber. In a feature of this aspect, the array of antennas oneach antenna disk is arranged in a ring whose center axis is orientedhorizontally. The rings include a first set of rings of antennas thatare transmitting and receiving antennas, and a second set of rings ofantennas that are receiving antennas only. The second set of rings isdivided into two subsets, and wherein the first set of rings of antennasis located between the two subsets. The first subset of rings includesone ring. The second subset of rings includes four rings. Each ringincludes 32 antennas.

In another feature, the image chamber unit further includes a flexiblemembrane separating a front portion of the imaging chamber from a rearportion of the imaging chamber. The flexible membrane conforms to aportion of the shape of a human head when the human head is insertedthrough the front entry opening and into the front portion of theimaging chamber. The rear portion of the imaging chamber is filled witha liquid. The liquid is a matching liquid for an electromagnetictomography operation. The matching liquid is a mixture of glycerol,water and brine. The antenna assembly further includes a back diskattached to a rear of a plurality of antenna disks, and wherein the backdisk includes at least one inlet for pumping the matching liquid intothe rear portion of the imaging chamber. In a further feature of thisaspect the image chamber unit of, further includes a catch basindisposed adjacent the entry opening so as to receive liquid leaking fromthe front of the imaging chamber. The catch basin includes a drain tube.The catch basin is attached to the image chamber unit. The catch basinis separate from, but positioned next to, the image chamber unit.

In a further feature of this aspect the image chamber further includes asanitary protective cap disposed in front of and against the flexiblemembrane to provide sanitary protection for a human head when the humanhead is inserted into the front entry opening and against the membrane.In yet a further feature of this aspect the image chamber furtherincludes a protective ring around the entry opening to protect the humanhead from injury when inserting the head through the entry opening.

In another feature, the electromagnetic tomography (EMT) system furtherincluded a patient support. The patient support includes a headrestextending therefrom so as to position and/or orient a patient's headwithin the imaging chamber. The image chamber unit is disposed on top ofthe patient support, on one end thereof, and wherein the control systemis carried beneath the patient support.

In another feature, the electromagnetic tomography (EMT) system furtherincluded a hydraulic system supplying liquid to the imaging chamber. Thehydraulic system includes a holding tank for the liquid and a pump. Theholding tank is a first tank, wherein the hydraulic system furtherincludes a second internal tank, and wherein the liquid flows from thefirst tank to the imaging chamber and from the imaging chamber to thesecond tank. In a further feature of this aspect an inline valve isdisposed between the first tank and the imaging chamber. In a furtherfeature of this aspect a backflow valve is disposed between the imagingchamber and the second tank. In a further feature of this aspect a checkvalve is disposed between the imaging chamber and the second tank inparallel with the backflow valve. In a further feature of this aspect atemperature sensor is disposed at an inlet to the imaging chamber. Aheater to raise the temperature of the liquid based on the status of thetemperature sensor. A liquid sensor that prevents heating if liquid isnot present in the second tank. In a further feature of this aspect, theelectromagnetic tomography (EMT) system includes an overflow path fromthe second tank. The overflow path connects the second tank back to thefirst tank. The pump includes a remote control. The pump is abi-directional pump.

Broadly defined, the present invention according to another aspect is animage chamber unit for gathering measurement data pertaining to a humanhead in an electromagnetic tomography (EMT) system, including: anantenna assembly at least partially defining a imaging chamber andincluding an array of antennas arranged around the imaging chamber, thearray of antennas including at least some transmitting antennas and atleast some receiving antennas, wherein the transmitting antennastransmit a low power electromagnetic field, wherein the receivingantennas receive the low power electromagnetic field after passingthrough a human head in the imaging chamber and provide correspondingsignals to a control system so as to produce a data tensor that may beinversed to reconstruct a 3D distribution of dielectric propertieswithin the human head and thereby to create an image of the object; ahousing, at least partially containing the antenna assembly, having anentry opening into the imaging chamber; a flexible membrane separating afirst portion of the imaging chamber from a second portion of theimaging chamber. The head of a human patient may be inserted through thefront entry opening and into the imaging chamber.

In a feature of this aspect the imaging chamber ishorizontally-oriented, wherein the entry opening is a front entryopening, wherein the first portion of the imaging chamber is at a frontof the imaging chamber near the front entry opening, and wherein thesecond portion of the imaging chamber is at a rear of the imagingchamber such that the flexible membrane separates the front portion ofthe imaging chamber from the rear portion of the imaging chamber. Theflexible membrane conforms to a portion of the shape of a human headwhen the human head is inserted through the front entry opening and intothe front portion of the imaging chamber. the rear portion of theimaging chamber is filled with a liquid. The liquid is a matching liquidfor an electromagnetic tomography operation. The matching liquid is amixture of glycerol, water and brine.

In a further feature the antenna assembly further includes a back diskattached to a rear of a plurality of antenna disks, and wherein the backdisk includes at least one inlet for pumping the matching liquid intothe rear portion of the imaging chamber.

In a further feature the image chamber unit further includes a catchbasin disposed adjacent the entry opening so as to receive liquidleaking from the front of the imaging chamber. The catch basin includesa drain tube. In a further feature of this aspect the image chamberfurther includes a sanitary protective cap disposed in front of andagainst the flexible membrane to provide sanitary protection for a humanhead when the human head is inserted into the front entry opening andagainst the membrane.

In a further feature the antenna assembly includes a plurality ofantenna disks, each antenna disk including an array of antennas. Eachantenna disk includes a center opening, wherein the imaging chamber isat least partially defined by the plurality of center openings. Theantenna disk center openings are circular and collectively define acylindrical portion of the imaging chamber. The antenna assembly furtherincludes a back disk attached to a rear of the antenna disks, whereinthe back disk closes and defines a rear of the horizontally-orientedimaging chamber. The array of antennas on each antenna disk is arrangedin a ring whose center axis is oriented horizontally The rings include afirst set of rings of antennas that are transmitting and receivingantennas, and a second set of rings of antennas that are receivingantennas only. The second set of rings is divided into two subsets, andwherein the first set of rings of antennas is located between the twosubsets. The first subset of rings includes one ring. The second subsetof rings includes four rings. Each ring includes 32 antennas.

In a further feature the image chamber further includes a protectivering around the entry opening to protect the human head from injury wheninserting the head through the entry opening.

Broadly defined, the present invention according to another aspect is amethod of using an electromagnetic tomography (EMT) system to generate adata tensor for imaging a human head, including: positioning a patienton his back on a patient support; inserting the head of the patienthorizontally through a front entry opening of an image chamber unit, theimage chamber unit including an antenna assembly at least partiallydefining a horizontally-oriented imaging chamber and including an arrayof antennas arranged around the imaging chamber, the array of antennasincluding at least some transmitting antennas and at least somereceiving antennas; and using a control system, causing the transmittingantennas to transmit a low power electromagnetic field that is receivedby the receiving antennas after passing through the patient's head inthe imaging chamber and producing a data tensor from resulting signalsthat may be inversed to reconstruct a 3D distribution of dielectricproperties within the human head and thereby to create an image of thepatient's head. The image chamber unit includes a housing that at leastpartially contains the antenna assembly, wherein the front entry openingis in the housing, and wherein the method further includes providing amembrane, within the imaging chamber, that separates a front portion ofthe imaging chamber from a rear portion.

In a feature of this aspect, the method includes a step of conformingthe flexible membrane to a portion of the shape of the patient's headwhen the head is inserted through the front entry opening and into thefront portion of the imaging chamber.

In a feature of this aspect, the method further includes a step offilling the rear portion of the imaging chamber with a liquid. Theliquid is a matching liquid for an electromagnetic tomography operation.The matching liquid is a mixture of glycerol, water and brine. Theantenna assembly further includes a back disk attached to a rear of aplurality of antenna disks, and wherein the method further includespumping the matching liquid into the rear portion of the imaging chamberthrough at least one inlet in the back disk. In a further feature ofthis aspect the method further includes a step of positioning a catchbasin adjacent the entry opening so as to receive liquid leaking fromthe front of the imaging chamber. The catch basin includes a drain tube.

In a further feature the method includes a step of placing a sanitaryprotective cap over the patient's head so that the protective cap isdisposed between the patient's head and the flexible membrane to providesanitary protection for a human head when the human head is insertedinto the front entry opening and against the membrane.

Broadly defined, the present invention according to another aspect is amethod of using an electromagnetic tomography (EMT) system to generate adata tensor for imaging a human head, including: in response to anemergency report and request from or on behalf of stroke patient,providing an ambulance equipped with an image chamber unit for gatheringmeasurement data pertaining to a human head in an electromagnetictomography (EMT) system, the image chamber unit including: an antennaassembly at least partially defining a horizontally-oriented imagingchamber and including an array of antennas arranged around the imagingchamber, the array of antennas including at least some transmittingantennas and at least some receiving antennas, wherein the transmittingantennas transmit a low power electromagnetic field, wherein thereceiving antennas receive the low power electromagnetic field afterpassing through a human head in the imaging chamber and providecorresponding signals to a control system so as to produce a data tensorthat may be inversed to reconstruct a 3D distribution of dielectricproperties within the human head and thereby to create an image of theobject, and a housing, at least partially containing the antennaassembly, having a front entry opening into the imaging chamber;positioning the stroke patient on his back on a patient support;inserting the head of the patient horizontally through the front entryopening of the image chamber unit and into the imaging chamber; using acontrol system, causing the transmitting antennas to transmit a lowpower electromagnetic field that is received by the receiving antennasafter passing through the patient's head in the imaging chamber andproducing a data tensor from resulting signals that may be inversed toreconstruct a 3D distribution of dielectric properties within the humanhead and thereby to create an image of the patient's head; providing thedata tensor to a hub computer system; producing EMT image results basedon the provided data; and providing the EMT image results to a medicalpractitioner at a treatment center for use in diagnosing or treating thestroke patient upon the patient's arrival at the treatment center.

In a feature of this aspect, the method further includes providing amembrane, within the imaging chamber, that separates a front portion ofthe imaging chamber from a rear portion. In a further feature of thisaspect, the method further includes a step of conforming the flexiblemembrane to a portion of the shape of the patient's head when the headis inserted through the front entry opening and into the front portionof the imaging chamber. In a further feature of this aspect, the methodfurther includes a step of filling the rear portion of the imagingchamber with a liquid. The liquid is a matching liquid for anelectromagnetic tomography operation. The matching liquid is a mixtureof glycerol, water and brine. The the antenna assembly further includesa back disk attached to a rear of a plurality of antenna disks, andwherein the method further includes pumping the matching liquid into therear portion of the imaging chamber through at least one inlet in theback disk.

In a further feature the method includes the step of positioning a catchbasin adjacent the entry opening so as to receive liquid leaking fromthe front of the imaging chamber. The catch basin includes a drain tube.

In yet a further feature the method includes the step of placing asanitary protective cap over the patient's head so that the protectivecap is disposed between the patient's head and the flexible membrane toprovide sanitary protection for a human head when the human head isinserted into the front entry opening and against the membrane

Further areas of applicability of the present invention will becomeapparent from the detailed description provided hereinafter. It shouldbe understood that the detailed description and specific examples, whileindicating the preferred embodiment of the invention, are intended forpurposes of illustration only and are not intended to limit the scope ofthe invention.

BRIEF DESCRIPTION OF THE DRAWINGS

Further features, embodiments, and advantages of the present inventionwill become apparent from the following detailed description withreference to the drawings, wherein:

FIG. 1 is a graphical illustration of the principle of electromagnetictomography (EMT);

FIG. 2 is a schematic view of a prior art EM field tomographicspectroscopic system;

FIG. 3 is a schematic diagram illustrating the operation of the systemof FIG. 1 in a two-dimensional context;

FIGS. 4 and 5 are schematic illustrations of two three-dimensionalsettings for the system of FIG. 2;

FIG. 6 is a front isometric view of an EMT system for imaging a humanhead in accordance with one or more preferred embodiments of the presentinvention;

FIG. 7 is a front plan view of the EMT system of FIG. 6;

FIG. 8 is a rear perspective view of the EMT system of FIG. 6;

FIG. 9 is a cross-sectional, partially schematic, right side view of theimage chamber unit of FIG. 7, taken along line 9-9;

FIG. 10 is a view of the image chamber unit similar to that of FIG. 9,but shown with a patient support and a catch basin in place adjacent theunit;

FIG. 11 is a view of the image chamber unit similar to that of FIG. 10,but shown with an upper portion of a patient's head inserted into theentry opening;

FIGS. 12 and 13 are a rear isometric view and a rear plan view,respectively, of the membrane of the image chamber unit of FIG. 6;

FIG. 14 is a side cross-sectional view of the membrane of FIG. 13, takenalong line 14-14;

FIG. 15 is a view of the image chamber unit similar to that of FIG. 11,but shown with a fluid disposed within the working chamber on theopposite side of the membrane from the patient's head;

FIG. 16 is a schematic diagram of the hydraulic system of FIG. 8;

FIG. 17 is a left front isometric view of portions of the disk assemblyof FIG. 9;

FIG. 18 is a schematic representation of concentric rings of antennas;

FIG. 19 is a top cross-sectional view of the disk assembly of FIG. 17,taken along line 19-19;

FIG. 20 is a front view of one of the antenna disks of FIG. 19;

FIG. 21 is a top cross-sectional view of the antenna disk of FIG. 20;

FIG. 22 is a schematic diagram of the EMT system of FIG. 6;

FIG. 23 is a schematic representation of the operation of the rings ofantennas around the imaging domain;

FIGS. 24A and 24B are a more detailed schematic diagram of the controlsystem of FIG. 22;

FIG. 25 is a schematic diagram of one of the transmitting/receivingswitch units of FIG. 22;

FIG. 26 is a schematic diagram of one of the receiving switch units ofFIG. 22;

FIG. 27 is a schematic diagram of the power unit of FIG. 22;

FIG. 28 is a schematic block diagram of additional or alternativedetails of a control system for the EMT system;

FIGS. 29 and 30 are a top front perspective view and a bottom rearperspective view, respectively, of another EMT system for imaging ahuman head in accordance with one or more preferred embodiments of thepresent invention;

FIG. 31 is a top plan view of the system in use in an ambulance;

FIG. 32 is a side perspective view of a cap serving as a wearable imagechamber unit in accordance with one or more preferred embodiments of thepresent invention; and

FIG. 33 is a pictorial illustration of a timeline for use of an EMTsystem, including the cap of FIG. 32, for imaging a human head inresponse to the onset of stroke symptoms in a patient.

DETAILED DESCRIPTION

As a preliminary matter, it will readily be understood by one havingordinary skill in the relevant art (“Ordinary Artisan”) that the presentinvention has broad utility and application. Furthermore, any embodimentdiscussed and identified as being “preferred” is considered to be partof a best mode contemplated for carrying out the present invention.Other embodiments also may be discussed for additional illustrativepurposes in providing a full and enabling disclosure of the presentinvention. As should be understood, any embodiment may incorporate onlyone or a plurality of the above-disclosed aspects of the invention andmay further incorporate only one or a plurality of the above-disclosedfeatures. Moreover, many embodiments, such as adaptations, variations,modifications, and equivalent arrangements, will be implicitly disclosedby the embodiments described herein and fall within the scope of thepresent invention.

Accordingly, while the present invention is described herein in detailin relation to one or more embodiments, it is to be understood that thisdisclosure is illustrative and exemplary of the present invention, andis made merely for the purposes of providing a full and enablingdisclosure of the present invention. The detailed disclosure herein ofone or more embodiments is not intended, nor is to be construed, tolimit the scope of patent protection afforded the present invention,which scope is to be defined by the claims and the equivalents thereof.It is not intended that the scope of patent protection afforded thepresent invention be defined by reading into any claim a limitationfound herein that does not explicitly appear in the claim itself.

Thus, for example, any sequence(s) and/or temporal order of steps ofvarious processes or methods that are described herein are illustrativeand not restrictive. Accordingly, it should be understood that, althoughsteps of various processes or methods may be shown and described asbeing in a sequence or temporal order, the steps of any such processesor methods are not limited to being carried out in any particularsequence or order, absent an indication otherwise. Indeed, the steps insuch processes or methods generally may be carried out in variousdifferent sequences and orders while still falling within the scope ofthe present invention. Accordingly, it is intended that the scope ofpatent protection afforded the present invention is to be defined by theappended claims rather than the description set forth herein.

Additionally, it is important to note that each term used herein refersto that which the Ordinary Artisan would understand such term to meanbased on the contextual use of such term herein. To the extent that themeaning of a term used herein—as understood by the Ordinary Artisanbased on the contextual use of such term—differs in any way from anyparticular dictionary definition of such term, it is intended that themeaning of the term as understood by the Ordinary Artisan shouldprevail.

Regarding applicability of 35 U.S.C. §112, ¶6, no claim element isintended to be read in accordance with this statutory provision unlessthe explicit phrase “means for” or “step for” is actually used in suchclaim element, whereupon this statutory provision is intended to applyin the interpretation of such claim element.

Furthermore, it is important to note that, as used herein, “a” and “an”each generally denotes “at least one,” but does not exclude a pluralityunless the contextual use dictates otherwise. Thus, reference to “apicnic basket having an apple” describes “a picnic basket having atleast one apple” as well as “a picnic basket having apples.” Incontrast, reference to “a picnic basket having a single apple” describes“a picnic basket having only one apple.”

When used herein to join a list of items, “or” denotes “at least one ofthe items,” but does not exclude a plurality of items of the list. Thus,reference to “a picnic basket having cheese or crackers” describes “apicnic basket having cheese without crackers,” “a picnic basket havingcrackers without cheese,” and “a picnic basket having both cheese andcrackers.” Finally, when used herein to join a list of items, “and”denotes “all of the items of the list.” Thus, reference to “a picnicbasket having cheese and crackers” describes “a picnic basket havingcheese, wherein the picnic basket further has crackers,” as well asdescribes “a picnic basket having crackers, wherein the picnic basketfurther has cheese.”

Referring now to the drawings, in which like numerals represent likecomponents throughout the several views, one or more preferredembodiments of the present invention are next described. The followingdescription of one or more preferred embodiment(s) is merely exemplaryin nature and is in no way intended to limit the invention, itsapplication, or uses.

FIG. 6 is a front isometric view of an EMT system 110 for imaging ahuman head 19 in accordance with one or more preferred embodiments ofthe present invention, FIG. 7 is a front plan view of the EMT system 110of FIG. 6, and FIG. 8 is a rear perspective view of the EMT system 110of FIG. 6. As shown therein, the system 110 includes an image chamberunit 131, a control cabinet 135, a hydraulic system 140 for supplying,circulating, and otherwise managing a matching fluid to the imagechamber unit 131, and a rolling carriage 132. In at least someembodiments, the image chamber unit 131 and the control cabinet 135 arehoused together in a single enclosure 134 and are supported on a rollingcarriage 132. Furthermore, in at least some embodiments, some or all ofthe hydraulic system 140 is supported on the rolling carriage 132 aswell. However, in some embodiments, the image chamber unit 131 andcontrol cabinet 135 are separate from each other and each may or may notbe carried on its own rolling carriage. In some of these embodiments,the image chamber unit 131 and control cabinet 135 are not located inthe same room. Although not illustrated in FIGS. 6-8, the system 110also includes a user interface computer 208, described elsewhere herein,which may be connected to the rest of the system 110 via Ethernet orother port 136 located on the side of the control cabinet 131.

FIG. 9 is a cross-sectional, partially schematic, right side view of theimage chamber unit 131 of FIG. 7, taken along line 9-9. As showntherein, the image chamber unit 131 includes a disk assembly 126, amembrane 133, and fluid inlets 167,168. The disk assembly 126 includes aplurality of antenna disks 170 and a back disk 183, wherein at least theantenna disks 170 are open in their centers. The center openings of theantenna disks 170 together with the back disk 183 at least partiallydefine a “working” chamber or “imaging” chamber 122. In at least someembodiments, the antenna disk center openings are circular, and thecircular openings thus define a cylindrical portion of the workingchamber 122 (perhaps best seen in FIG. 17), which simplifies theoperation of the tomography somewhat, but in other embodiments thecenter openings and working chamber 122 may take on other shapes. In atleast some embodiments, the volume of the working chamber 122 isapproximately 12 liters.

The center opening of the frontmost antenna disk 170 defines an entryopening 169 for receiving a patient. The entry opening 169 is preferablysurrounded by a protective ring 182 (shown in FIGS. 6 and 7) coveringthe surfaces of the antenna disk 170 and other portions of the workingchamber 122. FIG. 10 is a view of the image chamber unit 131 similar tothat of FIG. 9, but with a patient support 120 and a catch basin 165 inplace adjacent the unit 131, and FIG. 11 is a view of the image chamberunit 131 similar to that of FIG. 10 but shown with an upper portion of apatient's head 19 inserted into the entry opening. For comfort andconvenience, the patient may be positioned on the patient support 120,which may be a gurney, cart, table, stretcher, or the like. In at leastsome embodiments of the present invention, a headrest 118 extends fromthe end of the patient support 120. The headrest 118 is preferablypadded and adjustable. Adjustability of the headrest 118 may be providedin one or more of the longitudinal direction (toward or away from theend of the patient support 120), the vertical direction (up or downrelative to the patient support 120), and rotationally (for example,about an axis that is parallel with the end of the patient support 120).In the illustrated embodiment, the entry opening and the working chamber122 are sized to correspond specifically to a human head, but it will beappreciated that other dimensions may be utilized for other body partsor to accommodate the entirety of a human body. The entry opening issubstantially liquid-sealed by the membrane 133 such that the front ofthe working chamber 122 is separated by the membrane 133 from the rearof the chamber 122. Fluid leaks through the front of the working chamber122, such as around or through the membrane 133, may be captured in thecatch basin 165 disposed in front of the unit 131. It is contemplatedthat the catch basin 165 can be integral with or otherwise part of theimage chamber unit 131.

FIGS. 12 and 13 are a rear isometric view and a rear plan view,respectively, of the membrane 133 of the image chamber unit 131 of FIG.6, and FIG. 14 is a side cross-sectional view of the membrane 133 ofFIG. 13, taken along line 14-14. The membrane 133 is preferably somewhathat-shaped, with a center crown portion 127 extending “upward” or“inward” from an outer brim portion 128. The brim portion 128 is shapedto be fastened to the antenna disks 170 and may include apertures 129for this purpose. As shown in FIG. 14, the crown portion 127 may bethinner than the brim portion 128 and is preferably flexible enough towrap snugly around the patient's head 19, as shown in FIG. 11. In atleast some embodiments, the membrane 133 is made of latex or similarmaterial.

FIG. 15 is a view of the image chamber unit 131 similar to that of FIG.11 but shown with a fluid disposed within the working chamber 122 on theopposite side of the membrane 133 from the patient's head 19. The fluidmay be supplied to or from the working chamber 122 via the inlets167,168, which may be arranged in or on the back disk 183. The fluiditself is a “matching” fluid that is chosen for its properties so as toenhance the tomographic process. Flow and other movement of the fluid iscontrolled by the hydraulic system 140.

FIG. 16 is a schematic diagram of the hydraulic system 140 of FIG. 8. Asshown therein, the hydraulic system 140 includes an external tank 141, abi-directional pump 142, a valve 159, backflow valve 160, a check(directional) valve 161, an inner upper tank 146, one or more liquidsensors 147, a lighter 148, one or more temperature sensors 149,150, anda variety of hoses, tubes, fittings, and the like, some of which aredescribed herein. The external tank 141 holds a quantity of a matchingfluid. A hose 151 connects the external tank 141 to the pump 142, andanother hose 152 connects the pump 142 to a fitting 153 on the enclosure134. In at least some embodiments, the pump hoses 151,152 are ¾″flexible tube hoses, and the hose fitting 153 is a quick releasefitting.

The pump 142 is used to supply matching fluid from the external tank 141to the working (image) chamber of the image chamber unit 131. Thematching fluid is a solution or gel that is needed or useful inside theimaging chamber when the object 19 is being measured inside it toaddress electromagnetic body-matching problems. In at least someembodiments, the matching liquid is a mixture of glycerol (Ph. Eur.),water and brine. In at least some embodiments, the pump 142 is connectedby cable 154 to a standard power supply, such as a 220V electricalsource, which may be provided from the control cabinet 135 via an outlet137, preferably located on the outer surface of the enclosure 134, and acorresponding water proof socket 155. Direction, speed, and othercontrol of the pump 142 may be provided by remote control 156. One pump142 suitable for use in at least some preferred embodiments is a WatsonMarlow 620 RE IP66 pump.

Inside the image chamber unit 131, another hose 157 is connected betweenthe external fitting 153 and a first inlet 167 to the working chamber,and still another hose 158 is connected between a second inlet 168 tothe working chamber and the inner upper tank 146. In at least someembodiments, the hose 157 is a ¾″ flexible tube hose. An inline valve159 may optionally be provided in the hose 157 from the pump 134, whilea backflow valve 160 and check (directional) valve 161 may be providedin the hose 158 to the inner upper tank 146. The backflow valve 160provides at least two functions. First, when it is closed, the pump 142may be used to generate an under-pressure, thereby denting in themembrane 133 (as seen from outside the image chamber unit 131) andreadying the unit 131 for a patient's head to be inserted therein.Second, when the patient's head is positioned inside the membrane 133,opening the backflow valve 160 allows the matching fluid to flow fromthe reservoir 146 back to the imaging chamber, which in turn causes thepatient's head to be slowly enclosed by the membrane 133 and the liquid.The check valve 161, on the other hand, performs a safety function byavoiding the buildup of an overpressure if the backflow valve 160 isclosed. The check valve 161 includes a manual control lever 181, asshown in FIG. 6.

The temperature sensors 149,150 may be used to determine the temperatureof the matching fluid inside the working chamber, or in close proximitythereto. If the temperature becomes uncomfortably cool, the lamp orlighter 148 may be utilized to trigger heating of the inner upper tank146. Unintentional heating of an empty tank 146 may be avoided by usingthe liquid sensors 147 to verify that sufficient liquid is present inthe tank.

An overfill path may be provided between the inner upper tank 146 andthe external tank 141 so as to return any excess matching liquid to theexternal tank 141. The overfill path may include an internal hose 162,an external hose 163, and a fitting 164 on the exterior of the enclosure134, wherein the internal hose 162 is connected between the inner uppertank 146 and the fitting 164 and the external hose is connected betweenthe fitting 164 and the external tank 141. Generally, the overfill pathis only utilized if the reservoir 146 is accidentally overfilled, inwhich case the overfill path allows the excess liquid to return to theexternal tank 141. In at least some embodiments, the overfill path hoses162,163 are ¾″ flexible tube hoses, and the hose fitting 164 is a quickrelease fitting.

A leakage path may also be provided. The leakage path may include acatch basin 165 and a drain hose or tube 166. The catch basin 165 may bedisposed adjacent the working chamber so as to receive fluid escapingtherefrom, such as during dismantling of the system 110. In someembodiments, the drain hose 166 connects the catch basin 165 to theexternal tank, such as by the overflow path, while in others the drainhose 166 is routed to a waste tank (not shown) and/or is left open orunconnected.

FIG. 17 is a left front isometric view of portions of the disk assembly126 of FIG. 9. As shown therein, the disk assembly 126 includes aplurality of antenna disks 170 arranged concentrically such that theircenter openings define the interior of the working chamber 122, asdescribed previously. Notably, whereas traditional EMT systems have usedrings of transmitters/receivers/sensors that have been oriented in ahorizontal plane to define a vertical working chamber, the rings oftransmitter/receivers and receivers of the present invention are eachoriented vertically so as to define a horizontal working chamber. Eachantenna disk 170 includes a multitude of antennas 173 arranged in a ringaround the working chamber 122. FIG. 18 is a schematic representation ofthese concentric rings 180 of antennas 173. Although other numbers ofdisks 170 and rings 180 may be utilized, five antenna disks 170 and thusfive antenna rings 180 are present in the embodiment shown in FIGS. 17and 18. Furthermore, although other numbers of antennas 173 may beutilized, 32 antennas 173 are present in the embodiment shown in FIGS.17 and 18, and thus a total of 160 antennas 173 are utilized. In oneembodiment, preferred for its simplicity, the antennas 173 in the middlering 180 are both transmitting and receiving antennas, while theantennas 173 on the other four rings 180 are receiving antennas only. Inone contemplated embodiment, the rings 180 (i.e., the center openings ofthe antenna disks 170) are 285 mm in diameter. In FIG. 17,transmitting/receiving antenna “9” on ring “C” is shown as transmittingan electromagnetic field or signal, all or some of which is received ateach of various transmitting/receiving antennas on ring “C” and at eachof various receiving antennas on rings “A”, “B”, “D”, and “E”. It willbe appreciated, however, that any or all of the transmitting/receivingantennas on ring “C” and/or any or all of the receiving antennas on anyor all of the other rings may receive the transmitted field or signaland thus may be incorporated into the tomographic process.

FIG. 19 is a top cross-sectional view of the disk assembly 126 of FIG.17, taken along line 19-19; FIG. 20 is a front view of one of theantenna disks 170 of FIG. 19, and FIG. 21 is a top cross-sectional viewof the antenna disk 170 of FIG. 20. Notably, some visual detailregarding the electrical connections for the antennas has been omittedin FIG. 17; however, much of the omitted visual detail is shown in FIG.20. Each antenna disk 170 includes two mating rings 171,172, theantennas 173 themselves, a corner element 174 for each antenna 173, acable plate 175, and a cable assembly 176 for each antenna 173. Eachcable assembly 176 includes a cable and/or conduit with an appropriateterminator 177,178 on each end. Screws or other cable positioners 179are provided to hold the cable assemblies 176 in place.

FIG. 22 is a schematic diagram of the EMT system 110 of FIG. 6. As showntherein, the EMT system 110 includes the image chamber unit 131(including the working chamber 122), the hydraulic system 140, thepatient support 120, and a control system 200. The control system 200includes two 16-channel transmitting/receiving switch units 201 for thetransmitting/receiving antenna disk 170, two 16-channel receiving switchunits 202 for each of the receiving antenna disks 170, a control unit203, a network analyzer 204, a power unit 205, one or more fan units206, a hub 207, and a user interface computer 208. In at least someembodiments, the switch units 201,202, control unit 203, networkanalyzer 204, power unit 205, fan units 206, and hub 207 are supportedon a rack 209 in the control cabinet 135. The user interface computer208 may be supported on or in the enclosure 134 or may be supportedelsewhere, such as on a nearby desk, a user's lap, or in some cases evenoutside the room.

FIG. 23 is a schematic representation of the operation of the rings 180of antennas 173 around the imaging domain, which is defined by theimaging chamber. The general task is to make complex Si,j,k parametersmatrix measurement, where i is the transmitting antenna (i=1 . . . 32),j is the receiving antenna (j=1 . . . 31), and k is the ring of thereceiving antenna (k=1 . . . 5). The more practical case for the numberof receiving antennas that are measured for each transmitting antennamay be between 12 and 20 (i.e., only receivers generally opposite thetransmitting antenna), and the most practical case may be for 17receiving antennas to be measured for each transmitting antenna, butother numbers are also viable. Typical attenuations may be ˜90 dB to˜130 dB. In at least some embodiments, frequencies may be 0.8-1.5 GHz,step 50 MHz. In at least some embodiments, channel-to-channel isolationmay be ˜80 dB to ˜100 dB. In at least some embodiments, maximum poweroutput may be +20 dBm (100 mW). In at least some embodiments, singleframe data acquisition time may be less than 60 mSec (“frame” beingdefined as the full cycle of S matrix measurements). In at least someembodiments, the number of acquired frames may be from 1 to 1000. In atleast some embodiments, the dielectric properties of the matching mediabetween antennas and object may be ˜(30-to-60)+j(15-to-25).

FIGS. 24A and 24B are a more detailed schematic diagram of the controlsystem 200 of FIG. 22. As shown therein, the hub 207, which may provideboth wireless and wired connections, communicatively connects thecontrol unit 203, the network analyzer 204, and the user interfacecomputer 208. The control unit 203 includes a host controller thatinterfaces with the hub 207 as well as provides a trigger input to thenetwork analyzer 204 and receives “ready for trigger” and/or “busy”signals from the network analyzer 204. The host controller also receivesan ECG input and controls drivers for MW switches. The control unit 203also includes various circuitry, including amplifiers, multiplexers, andthe like, to generate input signals for the ports of the networkanalyzer 204, which may be a ZVA 4 port vector network analyzeravailable from Rohde & Schwarz. The network analyzer 204 is alsocommunicatively connected to the hub 207, preferably via a LAN, andoperations of the control unit 203 and network analyzer 204 are underthe control of the user interface computer 208. Power is supplied by apower converter which may receive 24V power from the power unit 205 asdescribed elsewhere herein.

FIG. 25 is a schematic diagram of one of the transmitting/receivingswitch units 201 of FIG. 22, and FIG. 26 is a schematic diagram of oneof the receiving switch units 202 of FIG. 22. FIG. 27 is a schematicdiagram of the power unit 205 of FIG. 22. As shown therein, the AC lineinput is converted into power for the hub 207, the network analyzer(VNA) 204, and for 24V AC/DC converters used to power the control unit203 and transmitter/receiver and receiver switch units 201,202. FIG. 28is a schematic block diagram of additional or alternative details of acontrol system for the EMT system 110.

In operation, a patient 15 is placed on his back on a patient support120 and transported to the image chamber unit 131, shown in FIG. 9, orthe image chamber unit 131 is transported to the location of the patient15. For sanitary purposes, a single-use protective cap (not shown) maybe placed over the patient's head 19. Such a protective cap may be madeof plastic, latex, or the like. The patient's head 19 is then insertedinto the entry opening 169 in the working chamber 122 as shown in FIG.11. The headrest 118 may be adjusted as necessary or desired to arrangethe patient's head in the desired position and orientation within theworking chamber 122. The patient's head 19 bears against the membrane133, which then conforms to the shape of the patient's head 19. With thepatient's head 19 properly arranged, a technician fills the workingchamber with a quantity of the prepared matching liquid. Filling may becarried out using the remote control of the pump, which in at least someembodiments has toggle switches to start and stop the pump, control thedirection of flow (in or out), and flow rate. Filling is preferablyinitiated at a low flow rate to avoid splashing of matching liquid.Matching liquid is pumped into the working chamber until it is full, asshown in FIG. 15.

In addition to filling the working chamber with the matching liquid, thetechnician may also power on the various electronic components,including the control unit, the network analyzer, transmitter andreceiver units, and the like. Using the user interface computer,software may then be utilized to calibrate and operate the system.Functionally, much of the operation of the EMT system 110 may be similarto that described in the aforementioned U.S. Pat. No. 7,239,731, U.S.Patent Application Publication No. 2012/0010493 A1 (U.S. patentapplication Ser. No. 13/173,078), and/or U.S. Patent ApplicationPublication No. 2014/0276012 A1 (U.S. patent application Ser. No.13/894,395), but various particular embodiments and features thereof maybe described herein. Measurements are taken, a matrix of complex data isgenerated, and various algorithms are used to transform such data intotomographic images of the interior of the patient's head 19.

Other embodiments of the present invention are likewise possible. Inparticular, EMT systems having components that are more easilytransported than those of the system 110 described hereinabove arepossible without departing from the scope of the present invention. Inthis regard, FIGS. 29 and 30 are a top front perspective view and abottom rear perspective view, respectively, of another EMT system 210for imaging a human head 19 in accordance with one or more preferredembodiments of the present invention. The system 210 includes an imagechamber unit 231, a control cabinet 235, and a hydraulic system 240 forsupplying, circulating, and otherwise managing a matching fluid to theimage chamber unit 231. The entire system 210 may be carried on apatient support 220, which again may be a gurney, cart, table,stretcher, or the like. In particular, the image chamber unit 231, whichincludes a built-in headrest 218, is carried on a top surface of thepatient support 220, near one end, and the control cabinet 235 iscarried beneath the patient support 220. Such a system 210 may be moreconveniently transported, and in particular, the system 210 may berolled with the patient support 220 onto and off of an ambulance andinto a medical facility. In this regard, FIG. 31 is a top plan view ofthe system 210 in use in an ambulance 211.

In at least some embodiments, an image chamber unit of a type describedherein is man-portable. As used herein, “man-portable” means cable ofbeing carried or borne by one human. In particular, an image chamberunit of a type described herein may take the form of a wearable hat,helmet, cap, or the like. FIG. 32 is a side perspective view of a capserving as a wearable image chamber unit in accordance with one or morepreferred embodiments of the present invention. Aspects of such wearableapparatuses may be described, for example, in U.S. patent applicationSer. No. 13/894,395.

At least some embodiments of the EMT systems presented herein, includingwithout limitation the mobile embodiments such as the one presented inFIGS. 29-31 and the wearable cap of FIG. 32, may be utilizedadvantageously outside of the clinical setting. FIG. 33 is a pictorialillustration of a timeline for use of an EMT system, including the capof FIG. 32, for imaging a human head in response to the onset of strokesymptoms in a patient. As shown therein, at 8:00 pm, a patient may beresting at home when he experiences the onset of stroke-like symptoms,such as disorientation and weakness in the face and arms. In response,he or a family member or friend contacts a medical provider, and anambulance is dispatched. Meanwhile, a doctor or other medicalpractitioner is contacted and updated on the situation. The patient'shead is placed in a mobile imaging unit, and scanning begins as shownaround 8:25 pm. (In FIG. 33, the mobile image chamber unit is the cap ofFIG. 32, but it will be appreciated that the unit of FIGS. 29-31 may beused instead.) Resulting data may be provided to the doctor, ambulancestaff, imaging specialists, and other personnel. Some of the data may beused directly for diagnosis, treatment, or the like, while compleximage-related data may be processed according to the systems and methodsof the present invention to reconstruct images from which furtherdiagnosis, treatment, or the like may be triggered. In at least someembodiments, such processing may generate an automatic alert that thedata indicates that a potential stroke is likely. Notably, in at leastsome embodiments, such processing is carried out by a third partyservice provider who specializes in reconstruction of images accordingto the systems and methods of the present invention. During transport,from approximately 8:45 pm to 9:00 pm, the cap 331 continues to providedata regarding the patient's condition, and the local hospital staff isfurther updated and arranges and prepares for further treatment. Oncethe patient arrives at the hospital or other treatment center, theimages and data may be used in providing timely, accurate informationabout the status of the stroke injury, and appropriate treatment andfollow-up may be administered. Such a system could be utilized toprovide the desired “under 3 hour” treatment that can make a majordifference in the final outcome of the stroke injury and its affect onthe patient.

It will be appreciated that in at least some embodiments, the systems,apparatuses and methods presented hereinabove may be incorporated into a4D EMT differential (dynamic) fused imaging system. 4D EMT differential(dynamic) fused imaging system suitable for use with one or morepreferred embodiments of the present invention are described in AppendixB.

Based on the foregoing information, it will be readily understood bythose persons skilled in the art that the present invention issusceptible of broad utility and application. Many embodiments andadaptations of the present invention other than those specificallydescribed herein, as well as many variations, modifications, andequivalent arrangements, will be apparent from or reasonably suggestedby the present invention and the foregoing descriptions thereof, withoutdeparting from the substance or scope of the present invention.

Accordingly, while the present invention has been described herein indetail in relation to one or more preferred embodiments, it is to beunderstood that this disclosure is only illustrative and exemplary ofthe present invention and is made merely for the purpose of providing afull and enabling disclosure of the invention. The foregoing disclosureis not intended to be construed to limit the present invention orotherwise exclude any such other embodiments, adaptations, variations,modifications or equivalent arrangements; the present invention beinglimited only by the claims appended hereto and the equivalents thereof.

What is claimed is:
 1. An electromagnetic tomography (EMT) system forgathering measurement data pertaining to a human head, comprising: (a)an image chamber unit including an antenna assembly at least partiallydefining a horizontally-oriented imaging chamber and including an arrayof antennas arranged around the imaging chamber, the array of antennasincluding at least some transmitting antennas and at least somereceiving antennas; (b) a control system that causes the transmittingantennas to transmit a low power electromagnetic field that is receivedby the receiving antennas after passing through a human head in theimaging chamber and produces a data tensor, from resulting signals, thatmay be inversed to reconstruct a 3D distribution of dielectricproperties within the human head and thereby to create an image of thehead; (c) a housing, at least partially containing the antenna assembly,having a front entry opening into the imaging chamber; and (d) aflexible membrane that substantially liquid-seals the front entryopening such that a front portion of the imaging chamber is separatedfrom a rear portion of the imaging chamber; (e) wherein the head of ahuman patient may be inserted horizontally through the front entryopening and into the imaging chamber.
 2. The electromagnetic tomography(EMT) system of claim 1, wherein the antenna assembly includes aplurality of antenna disks, wherein each antenna disk includes an arrayof antennas surrounding a center opening, and wherein the imagingchamber is at least partially defined by the plurality of centeropenings.
 3. The electromagnetic tomography (EMT) system of claim 1,wherein the flexible membrane conforms to a portion of the shape of thehuman head when the human head is inserted through the front entryopening and into the front portion of the imaging chamber.
 4. Theelectromagnetic tomography (EMT) system of claim 1, wherein the rearportion of the imaging chamber is filled with a liquid.
 5. Theelectromagnetic tomography (EMT) system of claim 4, wherein the liquidis a matching liquid for an electromagnetic tomography operation.
 6. Theelectromagnetic tomography (EMT) system of claim 5, wherein the antennaassembly further includes a back disk attached to a rear of a pluralityof antenna disks, and wherein the back disk includes at least one inletfor pumping the matching liquid into the rear portion of the imagingchamber.
 7. The electromagnetic tomography (EMT) system of claim 4,further comprising a catch basin disposed in front of, below, andadjacent to, the front entry opening so as to receive liquid leakingfrom a front of the imaging chamber.
 8. The electromagnetic tomography(EMT) system of claim 1, further comprising a patient support thatcarries the human patient.
 9. The electromagnetic tomography (EMT)system of claim 8, wherein the patient support includes an adjustableheadrest extending therefrom so as to position and/or orient thepatient's head within the imaging chamber.
 10. The electromagnetictomography (EMT) system of claim 8, wherein the image chamber unit isdisposed on top of the patient support, on one end thereof, and whereinthe control system is carried beneath the patient support.
 11. Theelectromagnetic tomography (EMT) system of claim 1, further comprising ahydraulic system supplying liquid to the imaging chamber, wherein thehydraulic system includes a holding tank for the liquid and a pump. 12.The electromagnetic tomography (EMT) system of claim 11, wherein theholding tank is a first tank, wherein the hydraulic system furtherincludes a second internal tank, and wherein the liquid flows from thefirst tank to the imaging chamber and from the imaging chamber to thesecond tank.
 13. The electromagnetic tomography (EMT) system of claim12, wherein an inline valve is disposed between the first tank and theimaging chamber.
 14. The electromagnetic tomography (EMT) system ofclaim 13, further comprising an overflow path from the second tank. 15.The electromagnetic tomography (EMT) system of claim 14, wherein theoverflow path connects the second tank back to the first tank.
 16. Theelectromagnetic tomography (EMT) system of claim 12, wherein a backflowvalve is disposed between the imaging chamber and the second tank, andwherein a check valve is disposed between the imaging chamber and thesecond tank in parallel with the backflow valve.
 17. The electromagnetictomography (EMT) system of claim 12, wherein a temperature sensor isdisposed at an inlet to the imaging chamber.
 18. The electromagnetictomography (EMT) system of claim 17, further comprising a heater toraise the temperature of the liquid based on the status of thetemperature sensor.
 19. The electromagnetic tomography (EMT) system ofclaim 18, further comprising a liquid sensor that prevents heating ifliquid is not present in the second tank.
 20. The electromagnetictomography (EMT) system of claim 11, wherein the pump is abi-directional pump and includes a remote control.